Flexible shaft coupling



y 12, 1953 R. IREDELL, JR 2,637,986

FLEXIBLE SHAFT COUPLING Original Filed Dec. 11, 1944 k JNVENTOR. R011 ert Iretle l J?- BY awfh ATTORNE S Patented May 12, 1953 URF-ICE corporatien ofiOhio Rubber Company; Akron; i Ohio,

lfiriginalapplication December11,. 1%4, Serial No.

31,,"1t351, Divided and this application "Janmy 10; 1951;Serial No. 265,380

(BL Be -i1) 3 3 Claims.

This inventioni'ela'tes' tofl'exible couplings and to na meth'orlfof malzing the same. It particu- 1ar1y --reiates to flexible couplings between driven aiid driving mernbers which permit a relatively lie angle of misalignment bet-Ween the shafts o 'res oelztive' members. 'Ihis isa'divisionof my co pending application Serial 0. 567,585 filed JD'ecember' 1lf'l944','noW"UfSfPatent No."-2',562',3 59.

lt has-been recognized that rubber and soft *viilcanized rubbery "polymers when "maintained under high compression are capable of sustaining much-greater'unitloading; either when such loads are applied in direct compression (Jr-in a direction sn'ch that' the rubber is deformed primarily by shearing stresses. 'It has "heretofore been proposed to utilize tubular'rubb'er'under radial com- =pression as aresilient coupling'b'etween driving =*an'd driven-members. However, to obtain relatively low torsional winclup under heavy' loading and to prevent hunting' between the driven and 'drivinamembers, it'is desirable to utilize "the rubber'in r'elatively'thin 'radiahsection. Such a relativelythin section of rubber under substan- 1 tialradial" compression, however," is subjected" to relatively excessive localized stresses when the shafts are not in substantial alignment and" this --"dfeet has 'limited 'the "field "of use of such COlLLfJlihgS.

It is an tbjec'stbf the' present invention to prov-i'cle fie'iiible couplings- 1which 'utilize only a relatively -small amount of 'r-ubber "initially under radial compression}'butwhieh 'permitcoupling' of rotatingishafts which are in siibstantialmis- Jltis aniobject of the present inventiori tdprovideialflexible shaft ooupling-whiehhas relatively low torsional 'winclup.

It 'isi'anotherobjectnf-the pYesent invention to provide? flexible shaft Ic'oi-iplingswhich havethe i aboveementioned desirable iaroperties or rubber "under thigh radial *com ression, which permit relatively-. great:'rnisa]ignment without' subjeeting portions "of the rubber I to excessive or deteriorating straimanclwhich maybereadily assembled 'together without' special apparatus.

it'risr still another tabjeot' of the-present inven- :tion to provide a method of making flexible t'counlings *whiohipermit relatively wide-angle "disa-tortion-rancl which are capable of transmitting high torquewithouti substantial wirioiup.

Othenobjeets will beiapparent from the" following description "of the sinventionas illustrated ":by' thee-accompanying drawings, in which EFigure: 1 isanrelevational View; partly in: section; or; a flexible--couplingi-embodying the presentinvention;

a couplings of t-the presentinvention Can vannular 1-22 iis' awertical sectional view .:of a: portion ofithevcoupling emborlyingnthe;present invention and? 'FllSQdi'IiIl'iflffGfillillEl itssassemblyrshowing -the first 5 aattapered :orfrustoeconioal; annular; rigid mem- 1 bar;

ia portionrof thenapparatus which mayi be step in'ither assembly ofrresilient:material within is verticalsectionalwview through a 'xportionof the cour'iling membersiiand :-a .portion 10 I offapparatustusecixiii thes assernbling, of: thereoncourt-he :ShEtft,FShOW'iIIQUthGUSBCOHd step in the assembling aoperation;

Fig. 4 is a vertical sectional view of; a l-modified i'fio'rm *of '"eoupling: embodyingnthe ipresent invenzt-ion is 2a=-vertioalsseetional view of another mo fled 'form of "couplingembodying ntheapresfentinvention.

i iliefiabovefobjetstsi are accomplished by utilizingaas aztorque+transmittingzresilienti member in rubber member under a statezoff'radialroompression antd 'having-a longitudinal rnonsuniform thiekness. zTherubbermemberl'haszsubstantially greater thicknesssadjacent the center "of 't-hef'cou- :1 pling or 'adjaeent' the :endbportioni' of at least one ofl'the: shaftsribeingacounlecl than: atthe: edge. of

the reonpling. -Since :Ia aportionsoftfthe :resilient material is of relatively thin seotion; thatipor'tion 1-' is'napaole-rof stransmitting relativelyhigh torque '3 withoutrzappreeiablekannular :Iclistortion andizthe rtexiclencyvforPhunting betweenv the shafts' is reecluced 5'00 minimum. By shaving I relatively great thickness near the end portion of the :shaft where theigreatest deflection due to: shaft mis- 1 alignment oefcurs;aagreatidegree of misalignment t between theeshaits is' readily taken care oi -without localized overheating of the-rubber.

:Referring 'lmOTE I particularly to uthe'zclrawing,

' in--which1liketpart5 aredesignatedsiby"like numera'ls of i'reference' "throughout 1 the s'everal views,

the couplings. of: the present invention have at least 'one g'portionx'A :or: B acompris-ing an "inner rigidr'member lot-:01" i'b, which may:be aiclriven vor:driving shai't': ora member":makingirigid eonneotion "with'rthe "same and which preferably 1 an outer cylindriealisurface 3 anout'er. rigid member l with alongitu'dinally or axially: tapered innerwsurfaoe s2 atan angle to the "outer earface 3, oirthe inner memberygan annular resilient nmembeiwfi, which -isz=of rubberlike material, a soft vulcanized: rubberi or synthetic rubber icomgouncl eand which has :portions thereof under substantial radialvcompression :between said inner and outer rigid r members, :zand' inra'dherent wnon-slippi-ng 1 union i therebetween; rand :rmeans such as a collar or housing portion T of said outer rigid member for connecting said outer rigid member to a shaft or outer rigid member of another portion. The outer rigid member may be annular, in one piece, as shown in Figs. 1 to 5.

In accordance with the present invention, the separation between the inner and outer members of at least one portion A or B is variable in a longitudinal or axial direction, the maximum separation occurring near the end of the shaft or inner member. The resilient material is in the deformed state in the coupling, wedge shaped in cross-section, or has greater thickness adjacent the end portions ll) of the shaft or shaft portion where greatest strain is ordinarily had due to misalignment of driving and driven shafts.

The outer rigid member 4 is preferably tapered or has frusto-conical shape with an inturned portion 8 adjacent the widest end thereof to assist in retaining the formed resilient material in the desired shape prior to assembly of the portions of the couplings. Frictional means is preferably provided between the outer surface of the rigid member 4 carried by one shaft and a cooperating element carried by the other shaft, so that driving torque is not transmitted by the housing member 1. Thus, the outer face 9 of the inturned portion or lip portion 8 is preferably irregular, as may be obtained for example by knurling or the like, so that upon abutment with a corresponding inturned portion of a cooperating portion, no slippage will occur.

In the modification of Figure l, the portions A and B carried by each of the driving and driven shafts Ia and lb, respectively, are substantially identical. The portions 1a and lb of the housing, which serve as means for exerting axial pressure against the outer rigid members 4 and thus connect the outer members 4 of one section in driven relation to the shaft of the second section, are threaded together.

In the modification of Fig. 4, section B of Fig. 1 is substituted by a housing portion To, which is rigidly carried by the shaft lb.

The modification of Fig. 5 is similar to that of Fig. 1 except that the housing portion la is threaded directly onto the outer rigid members 4 of one of the sections.

In the preparation of couplings embodying the present invention, the resilient member 5 may be assembled within the outer rigid member 4 and the shaft or inner member la, assembled in concentric relation in substantially the same manner as set forth in the Thiry Patent No. 1,782,770. Thus, referring to Figs. 2 and 3, the resilient member 5, which may have a rectangular or oblong cross-section and which preferably has a volume sufficiently large to fill the space between the outer surface 3 of the shaft or inner member and the inner surface 2 of the outer rigid member of the coupling, is forced by suitable means such as a plunger l2. The plunger l2 slides within the guides l3 through a tapered path within the guide l4 into the outer member 4. The diameter of the bore I5 within the annular resilient member 5. while disposed within the outer member 4, is sub: stantially less than the outer diameter of the outer surface 3 of the shaft or inner member.

The shaft or inner member 3 is preferably provided with a tapered leader IS, the smallest end of which is sufliciently small to enter into the bore and the largest end of which may be approximately equal to the diameter of the outer surface 3. By relative axial movement between the member 4 and the resilient material 5 within the outer member 4, the outer surface of the inner member 3 may be readily disposed within the bore l5 of the resilient material 5 concentric with the inner surface 2 of the rigid member 4, thus causing substantial deformation of the resilient material and a firm non-slipping union between the surface of the inner member and the inner surface of the outer member.

A lubricant which is readily absorbed by the resilient material 5 or a rubber-to-metal adhesive may be applied between the surface 3 or the surface of the leader member and the resilient material 5 during the assembly operation. The outer member 4 may also be adhesively bonded to the resilient material 5 and, if desired, the resilient material 5 may be molded and cured within the outer member 4 substantially as shown in Fig. 3. In such case the internal bore I5 of the mold member should be substantially smaller than the shaft or inner member.

If desired, the outer rigid member 4 may also comprise a plurality of longitudinal sections adhesively bonded or otherwise attached to the annular resilient member 5 at the external surface thereof. If the member 4 comprises a substantial number of sections attached only over a portion of their Width to the resilient member 5, the resilient material and the outer rigid member 4 may be applied over the shaft or inner member by simply stretching the resilient member 5 to enlarge its internal bore and cause separation of the respective sections of the rigid member 4. The resilient material may then be compressed within a collar or housing portion 1a, similar to that illustrated in Fig. 4, radial compression being obtained by relative slippage of the members Ia and 4 during the threading of the collar on the member 10.

Since the thickness of the resilient material 5 is adjacent the ends Ill of the shaft upon which they are carried, it is seen that greater easeof flow of resilient material or ease of distortion is had adjacent the ends of the shaft and failure due to substantial misalignment is therefore less likely.

Although several embodiments of the invention have been herein shown and described, it will be understood that numerous modifications of the construction shown may be resorted to without departing from the spirit of this invention as defined in the appended claims.

What I claim is:

1. A flexible coupling for rotating shafts comprising an annular resilient member disposed over an end portion of one of said shafts having substantially greater thickness adjacent said end portion, an outer member of rigid material having longitudinally tapered annular inner surface portions substantially concentric with the outer surface of said shaft and disposed over and bearing against an outer surface of said annular resilient member, portions of said tapered annular inner surface of said outer member bearing strongly against said outer surface of said resilient member and being of smaller diameter than that of corresponding contacting portions of said resilient member in its free state, whereby said resilient member is radially compressed between said shaft and said outer member, and a connector for connecting said outer member in driving relation to the other shaft.

2. A flexible coupling for rotating shafts comprising an inner shaft portion connected with a remaining portion of one of said shafts, an annular resilient member wedge-shaped in crosssection disposed over a portion of an outer surface of said shaft portion, and an outer member of rigid material having longitudinally tapered outer and inner surfaces substantially concentric with the outer surface of said shaft portion and bearing against an outer surface of said annular resilient member, portions of said outer member contacting said resilient member having a diameter less than the diameter of corresponding portions of said resilient member in the radially uncompressed state on said shaft portion, whereby said resilient member is compressed between said shaft and said inner surface of said outer member, and a connector for connecting said outer member in driving or driven relation with another shaft.

3. A flexible coupling for use between rotating shafts having at least one portion comprising an inner rigid shaft portion for connection to one of said shafts, an outer member of rigid material with a longitudinally tapered inner surface substantially concentric with the outer surface of the shaft portion, and an annular resilient member wedge-shaped in cross-section between said inner surface of said outer member and said shaft portion, and having its outer surface bearing against the inner surface of said outer member, the diameter of portions of said inner surface of said outer member bearing against portions of said annular resilient memher being of lesser diameter than the diameter of the corresponding portions of said annular resilient member when in its radially uncompressed state with its inner surface bearing against an annular portion of the outer surface of said inner member, whereby said annular resilient member is under substantial radial compression between the outer surface of said shaft portion and the inner surface of said outer member and connects said outer member and said shaft portion in relatively nonslip relation, and connecting means for connecting said outer member in driving relation to the other of said shafts.

ROBERT IREDELL, JR.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,772,915 Rosenberg Aug. 12, 1930 1,871,963 Dill Aug. 16, 1932 1,983,094 Neher Dec. 4, 1934 2,084,761 Bradley June 22, 1937 2,295,316 Yates Sept. 8, 1942 2,562,359 Iredell July 31, 1951 FOREIGN PATENTS Number Country Date 207,400 Great Britain 1923 

